hi jgarreth! I wish you great luck in getting a new ordinance passed.
I have found that many municipalities like to look at what other municipalities have done and whether it worked for them. I would recommend that you look at other places that have 'been there and done that' and look at the codes they have on the books that allow chickens.
For instance, to find fencing requirements or setbacks, simply google animal enclosure setbacks and pick through to find actual codes that are on someone else's books. Here is one from
http://www.qcode.us/codes/escondido/view.php?topic=33-9-33_145 :
Sec. 33-145. Animal enclosure setback requirements.
(a) Animal enclosures shall be set back from property lines as follows:
(1) Side yard: fifteen (15) feet;
(2) Rear yard: ten (10) feet.
(b) Animal enclosures shall be set back from any residence twenty (20) feet.
So you could modify the wording to say something like:
(a) With the exception of properties that have a 6 foot privacy fence between the chicken enclosure and the neighboring properties, chicken enclosures shall be set back from property lines as follows:
(1) side yard: fifteen (15) feet (or whatever you decide)...etc...
of course you may want to eliminate the word enclosure and say pen, area or some other descriptive word for where the chickens are to be kept.
If you are really industrious, you could call the municipalities and talk to the folks that administer the codes and see what they say works or doesn't work for them.